1. Field of the Invention
The present invention relates to a liquid ejection apparatus having a liquid ejection surface in which a plurality of liquid ejection ports for ejecting liquid are arranged, and to a liquid ejection surface cleaning method for cleaning a liquid ejection surface in which a plurality of liquid ejection ports are arranged.
2. Description of the Related Art
Conventionally, a liquid ejection apparatus is known which ejects liquid onto an ejection receiving medium, such as paper, by using a liquid ejection head (hereinafter, simply called “head”) comprising liquid ejection ports which eject liquid, pressure chambers which connect to the liquid ejection ports, and pressure generating elements which generate a pressure inside the pressure chambers in order to eject liquid from the liquid ejection ports. An image is formed on an ejection receiving medium by means of an ink containing a coloring material being ejected onto the ejection receiving medium by means of a liquid ejection apparatus of this kind.
Japanese Patent Application Publication No. 2002-166560 describes an apparatus comprising: a cap (capping mechanism) which caps the liquid ejection ports of a head; a suctioning device which suctions ink, and the like, from the liquid ejection ports, by generating a negative pressure inside the cap by connecting the cap in a capping state and operating the pump; and a wiping device which wipes away foreign matter adhering to the liquid ejection surface of the head.
Japanese Patent Application Publication No. 7-96604 discloses an apparatus comprising: a head; a head drive device which selectively outputs a first signal for generating an ink droplet at a speed suitable for printing and a second signal for causing ink to seep out from liquid ejection ports; a cleaning apparatus which is normally positioned in the non-printing region and is movable in the lengthwise direction of the head during cleaning; a drive device which moves the cleaning apparatus relatively in the lengthwise direction of the head; a cleaning apparatus position determination device which determines the position of the cleaning apparatus; and a device which, on the basis of a cleaning command, determines the position of the cleaning apparatus by means of the cleaning apparatus position determination device and drives the pressure generating elements by means of the head drive device so as to cause ink to seep out from the liquid ejection ports in the vicinity of the position of the cleaning apparatus.
However, it is difficult to clean the liquid ejection surface satisfactorily while suppressing wasteful consumption of ink.
For example, in a mode where the head is covered with a cap and the ink is suctioned, in general, the majority of the ink is suctioned into the cap without adhering to the liquid ejection surface, and therefore it is difficult to remove satisfactorily any matter adhering to the liquid ejection surface. In order to make the ink adhere satisfactorily to the liquid ejection surface, it is necessary to fill the space between the cap and the liquid ejection surface of the head capped by the cap, with ink, but in a case of a matrix head having a plurality of liquid ejection ports, the cap is large in size and therefore a very large amount of ink is required, in addition to which the amount of ink adhering to the liquid ejection surface is restricted and hence the ink use efficiency is poor. In other words, it has been difficult to suppress wasteful consumption of ink, while at the same time cleaning the liquid ejection surface satisfactorily.
Furthermore, a mode can be envisaged in which ink is ejected towards a wiping device while foreign matter adhering to the liquid ejection surface is being wiped away with the wiping device, but this is problematic in that the ink is scattered about the periphery of the wiping device and soils the interior of the apparatus.
Moreover, in a mode which uses signals that cause ink to seep out from the liquid ejection ports, then although the vicinity of the liquid ejection ports is wetted with ink, areas which are distant from the liquid ejection ports are not wetted with ink and do not become wet, which means that material adhering to the liquid ejection surface cannot be removed satisfactorily. If the waveform is made larger in order to increase the amount of ink seeping out, then ink ejection will occur and consequently, it will not make the liquid ejection surface assume a wet state. In other words, it has been difficult to suppress wasteful consumption of ink, while at the same time cleaning the liquid ejection surface satisfactorily.